Field of Invention
This invention relates to an exercise device for exercising the major muscles comprising the gluteal region, while providing a full range of motion to assure effective toning and strengthening of the muscles of that region. It is well known in the fitness industry that exercises that are specific to particular muscles and/or to portions of the those muscles, best suited to optimally strengthen and tone the principal muscles in the gluteal region.
Ordinarily, movements of non-weight bearing joints are described by the movement of the distal part in relation to the proximal part e.g. the knee in relation to the hip or the foot in relation to the knee. The hip joint is functionally unique since in weight bearing postures, i.e., standing or walking, the foot is planted on the floor. When the foot is planted on the floor the pelvic ischium bones may move on the femur, rather than the femur moving on the pelvis such as occurs when bending forward at the waist to pick something off the floor. This movement is controlled by the hip joint muscles. When one comes back up from the bent position, the hip muscles initiate and control the movement of the trunk back to the erect position. Therefore, strong buttock muscles provide a safety feature to the functional movements of the spine. Weak hip muscles, and in particular the buttock muscles, cause excessive strain on the lower back muscles by requiring the lower back muscles to bring the trunk up from the forward bent position, or in even more common movements, such as when raising the body up and out of a seated posture.
Muscles work in groups to move a body part. These groups are called the synergist muscles, the agonist muscles and the antagonist muscles. The muscles relevant to exercising and toning the gluteal region are the synergist and agonist muscles of the hip joint.
The synergist muscles are generally the small muscles of the joint that serve to hold the joint in place and thus provide an anchoring of the joint about which a movement can occur. In the hip joint these muscles are the: gemellus superior; gemellus inferior, quadratus femoris, obturator externus, obturator internus and piriformis muscles. The synergist muscles are best exercised with the use of free weights since these muscles arc called into action to maintain the hip joint in a particular plane of motion. Free weight exercising is more desirable than machines which operate on a track, because track machines do not require the hip synergist muscles to stabilize the joint in a particular plane of motion while the exercise is performed.
The agonist muscles are the prime mover muscles that are specifically addressed with exercise. In the hip joint, these muscles are the gluteus minimis, gluteus medius and gluteus maximus muscles. These are commonly referred to as the buttocks. The gluteus maximus and the gluteus medius muscles are twisted counterclockwise on themselves so as to attach to the femur of the hip bone and cause extension of the hip and external rotation of the hip simultaneously. The gluteus medius is attached to the front portion of the hip and acts to extend and internally rotate the hip. An exercise device must take these movements patterns into account to effectively exercise all three muscle. Most people are only familiar with the gluteus maximus muscle, yet the overall definition of the buttock area involves the exercising of all three muscles.
The ranges of motion of the hip joint are:
Flexion (antagonist movement) of the hip joint is movement of the knee forwardly toward the fixed trunk or of the pelvis forwardly towards the fixed thighs as in bending forwardly at the trunk to pick something off of the floor. The range of motion from the leg straight position, with the knee bent to slacken the rectus femoris muscle, (zero point) is about 125 degrees.
Extension (agonist movement and synergist movement) of the hip joint is movement of the knee backwardly away from the trunk or of the pelvis backwardly as in returning the trunk from the forward bent position to the upright position. The range of motion from the leg straight position (zero point) is about 10 degrees. Therefore the total range of hip joint flexion and extension movement is about 135 degrees.
Adduction (antagonist movement) of the hip joint is movement of the knee downwardly toward the floor in the side-lying position or of the pelvis sideways and upwardly toward the rib cage. The Adductor muscles are the antagonists to gluteal exercise movements. The range of motion from the leg straight position (zero point) is about 10 degrees.
Abduction (agonist movement and synergist movement) of the hip joint is movement of the knee upwardly from the floor in the side-lying position or of the pelvis sideways and downwardly toward the hip joint. The pelvic movement occurs if the load to hip joint exceeds the strength of the back muscles which control the lateral pelvic movement. Therefore, proper positioning for training the gluteal muscles also helps train the lateral back muscles. The range of motion from the leg straight position (zero point) is about 45 degrees. Therefore the total range of hip joint adduction and abduction movement is about 55 degrees.
Medial Rotation (antagonist movement) of the hip joint is movement of the thigh inwardly or of the pelvis rotating clockwise on one femur at a time such as occurs when the right foot is planted on the floor and the trunk is toward the right hip (the "twist" dance move). The range of motion from the leg straight position (zero point) is about 60 degrees.
Lateral Rotation (agonist movement and synergist movement) of the hip joint is movement of the thigh outwardly upwardly from the floor in the side-lying position or of the pelvis rotating counter-clockwise on one femur at a time such as occurs when the right foot is planted on the floor and the trunk is turned toward the left hip (the "twist" dance move). The range of motion from the leg straight position (zero point) is about 90 degrees. Therefore the total range of hip joint lateral and medial rotation is about 150 degrees.
Thus, to effectively exercise the agonist and synergist muscles of the hip, the motions of extension, abduction and lateral rotation must be included in the exercise motion. Conventionally these muscles are exercised separately. Since these muscles act in a coordinated fashion to provide functional movements to the body, and in particular to prevent displacement of stress to the spine, it is desirable to exercise all three muscles in a functional pattern throughout the full range of hip joint motion. The conventional buttock exercise has been, up to now, the donkey kick back technique. This technique is performed with the exerciser in the quadruped stance (on all fours) and the leg to be exercised is bent at the knee then raised straight upwardly in a manner so as to push the sole of the foot up towards the ceiling in a slight arcing motion. In order to more effectively isolate and exercise all three of the gluteal muscles the exercise is also performed by bringing the knee inwardly towards the opposite hip and then upwardly and then outwardly towards the same hip and then upwardly. Some machines, incorporate a track on which the motion is restricted to the straight upward motion thus exercising specifically only the gluteus minimum portion of the gluteal muscle group.
This "donkey kick" exercise motion is not an effective functional exercise, i.e., exercise which supports and promotes functional body movement and thereby strong, coordinated action of the body which effectively serves as a prophylactic against bodily injury. The problem arises because this exercise motion is extremely hazardous to the anatomy of the pelvis and lower back and may cause, if done too quickly or in a jerking motion, excessive strain to the lower back and pelvic joints. Though one may substantially prevent injury from occurring by performing the motion with correct tempo and technique, there remains an increase in potential for injury when the exercise is performed to the point of muscle fatigue. This is a double edged sword, for it is imperative that a muscle, or muscle groups be challenged to fatigue in order to get the desired results. Adding resistance to the leg while performing this exercise, such as an ankle weight, or, in the case of the gym machines, a weight stack, causes the exerciser to tend to perform the exercise with jerky movements in order to initially overcome the resistance and thus negate any safety of the exercise provided by proper technique or form.
Furthermore, in conventional free hand exercises and those involving the use of weights, the back is kept either in a vertical or horizontal position. Exercises in these positions tend to cause the back to arch which can result in discomfort and fatigue of the back as well as potential injury to the back as the lower back is rotated or flexed in an unsafe manner. The pelvic joint termed the sacroiliac joint must be protected when exercising the buttock muscle groups. As previously mentioned the conventional "donkey kick" wherein the exerciser is on all fours and the hip is extended, causes the pelvic bones to lock at the full extent of flexion range of motion of the sacroiliac joints and thus the lower back is strained by excessive extension or swayed back movement especially when complicated by the weight of the abdomen which assists the swaying motion of the lower spine. Again, this can be avoided if the hip is not excessively extended, however, a compromise of the hip buttock exercise is given up by avoiding full range of motion extension of the hip joint. Furthermore, a common cause of low back pain is sacroiliac joint fixation. The "donkey kick" exercise method may result in strain of the sacroiliac joints and lead to the onset of low back pain.
For maximum benefit exercises should be performed in the optimal safe posture and in the correct planes of motion so as to effectively exercise both the muscles that are desired to be targeted, in this case the gluteal muscles, and at the same time strengthen the synergistic muscles which hold the joint in optimum position for body function. The exercise should also provide a body position which reduces substantially any risk for displacement of the load and thereby strain to another anatomical area, such as the pelvic joints or the joints of the lower back.
In order to train for strength, the exerciser must not allow a muscle or muscle groups to adapt to the resistance load. This is accomplished by progressively increasing the resistance or load to the muscle or muscle groups or alternatively by positioning the load at the end or along various lengths of the body lever, in this case the leg. Various resistance-type exercise devices for exercising muscles of the gluteal region are known. However, it has been found that when a person undertakes a program of conditioning the muscles of the gluteal region by systematic use of such a device, that person often soon abandons the program because the resistance is so great as to allow performing only a few repetitions before fatigue sets in, or so small that the muscles are not adequately stressed regardless of how many repetitions are done.
Even if the resistance is initially in an appropriate range for a users muscular strength, he or she may find as the muscles become stronger through exercise, that a conditioning plateau is reached where the set resistance is insufficient to provide further strengthening, thereby necessitating a need for a means to progressively increase or vary the resistance. As is well known, the preferred method for strengthening muscles is exercise using progressively increasing resistance because this places increasing demand on muscles and prevents them from accommodating them to a specific force. Thus, to enable a resistance-type device to be used effectively by individuals having different strength and to enable an individual who progresses through an exercise program to remain challenged as his or her strength increases, there is also a need for an exercise device for the gluteal region that not only meets the above-stated criteria but also one in which the resistance can be conveniently increased or decreased.
The present invention provides a freedom of range of motion, thus requiring the exerciser to stabilize the joint with the synergistic muscles in order to accomplish the exercise movement involving abduction, external rotation and extension of the hip joint, since the plane of motion of the hip joint changes from the start point and throughout the exercise motion to the finish point of the exercise. In addition, the present invention performs the exercise in the side-lying posture. This has the benefit of preventing strain of the sacroiliac joints while unloading the lower spine from the weight of the abdomen to effectively permit a safe full range of motion of the hip joint into extension.
The present inventions includes, in a preferred embodiment, elastic cords that can be adjusted to increase the applied resistance to provide for progressive and variable resistance, a necessary feature of any serious strength training machine. Furthermore, since the attachment to the leg is at the foot, which is the end of the leg lever, the resistance is always at an optimum position for maximum resistance to the movement. A further advantage gained from the position of the resistance anchor at the foot is the incorporation of ankle and knee stabilizing muscles thus ensuring an overall leg strengthening and toning. In particular the muscles forming the peroneal muscle group on the outside of the lower leg are commonly weak in individuals which is a common cause of recurring ankle sprains. Also, the present invention exercises the tensor fascia latae muscle. This muscle is a smooth flat muscle located on the outside of the thigh and gives a properly toned thigh it's characteristic sleek shape.